We have analyzed cross sectional data from the Prospective Cohort of Older Puerto Ricans for the effects of proximity to major roadways and density of traffic near their residences. This analysis did not assess levels of pollution because the cohort study was not originally designed to assess this exposure. Still, using traffic as a proxy, we have demonstrated associations between traffic proximity and hypertension, blood pressure, C-reactive protein and serum albumin. To oiu- knowledge this is the first study to assess traffic exposure and cardiovascular disease (CVD) markers in a Puerto Rican population, a population that has high prevalence of risk factors and cardiovascular diseases. There is competing evidence that fine particulate matter (PM2.5) is associated with CVD. However, this fraction of PM is spread fairly evenly across geographic areas with variation within cities, but little increase next to heavy traffic. Ultrafine particulate pollution (UFP), which are extremely small particles have, however, been shown to be elevated locally near highways and heavily traveled roadways. Research besides ours also has shown associations between proximity to traffic and CVD. Thus, we will address both the role of traffic pollution in health disparities in the Puerto Rican population and develop evidence about whether there is a causal link between UFP and CVD. We propose three community-based participatory research studies that actively engage our community partners in the research process. Study one will build on our preliminary work and develop a model of UFP exposure across our study area in order to test associations of ambient UFP exposure with CVD in the core cohort (project 1 for the center). Study two will install HEPA air filtration in homes of 20 participants in the core cohort and assess whether reducing UFP in the home is associated with improvements in markers of inflammation, including C-reactive protein, IL6, fibrinogen and TNF-a. Study three will develop and disseminate educational materials about traffic-related pollution and CVD to the local Puerto Rican population.